1. Field of the Invention
The invention relates to a resilient support for a below-knee orthotic device for an articulated connection of a below-knee cuff to a foot cuff.
2. Description of the Related Art
Resilient supports of this type are employed, for instance, in below-knee orthotic devices for patients having deep paralyses, in the case of muscular illnesses, infantile cerebral pareses, pathologic illnesses, neurological changes or else with healthy individuals to support the function of the plantar flectors. By the below-knee orthotic device the foot is supported with respect to the lower leg, at the same time energy being absorbed by the resilient support during the step-on and standing phase and being released during the push-off phase.
The FIGS. 1 and 2 show a known resilient support as well as a below-knee orthotic device. The figures are based on the applicant's below-knee orthotic device SPRING and can be taken from the catalogue Medizinisches Verordnungsprogramm1 by Gottinger GmbH, 85604 Zorneding. The below-knee orthotic device 2 includes a below-knee cuff 4 to encompass a lower leg 6 and a foot cuff 8 for fixing a foot 10. The two cuffs 4, 6 are articulated to each other via a resilient support 12 having a lower leg-side end portion 14 and a foot-side end portion 16, wherein the lower leg-side end portion 14 is accommodated in the below-knee cuff 4 and the foot-side end portion 16 is accommodated in a sole 18 carrying the foot 10. In order to assist the spring force, a heel part 20 of the resilient support 12 is curved in the opposite direction. 1Medical Prescription Range
What is a drawback of this known solution is that the spring rate of the resilient support is designed so that the best possible support is given in the push-off phase during walking. Due to the coordinated movement during walking the resilient support must develop a higher supporting force in the push-off phase than in the step-on phase, however, so that when making use of the known solution no “soft” step-on is possible and thus “the resilient support is pushed into the knees”, which is annoying, or a strong rebound of the foot toward the knee takes place.
It is moreover a drawback that for executing an independent plantar flexion of the foot by muscle strength, as it is necessary, for instance, to operate the foot pedals when driving a motor vehicle, a patient must always apply a high counter-force due to the high spring rate so as to counteract the spring force of the resilient support.
It is the object of the present invention to provide a resilient support which eliminates the afore-mentioned drawbacks and is inexpensive to manufacture.